The invention relates to an adjustable hydraulic axial piston machine of dry case type of construction, as per claim 1.
A hydraulic axial piston machine of said type is known for example from DE 44 14 509 C1. It is stated in said document that, in the case of conventional hydraulic machines, the case is constantly filled with liquid owing to inevitable pressure fluid leakage. As drive assembly parts rotate in the liquid-filled case, energy losses occur, which are referred to as splashing losses. To reduce splashing losses, it is advantageous, in particular in the case of operation at high rotational speeds, for the liquid to be removed from the machine case in order that the drive assembly rotates in a case that has been emptied of oil. For the removal of liquid from the case, various methods have been proposed which are based on the extraction of the leakage liquid by suction. The type of construction of hydraulic axial piston machines realized in this way is referred to as the dry case type of construction. Such hydraulic axial piston machines with pump devices for the extraction of leakage fluid by suction are described for example in DE 44 14 509 C1, DE 42 15 869 C1 and DE 41 28 615 C1. The invention is based on an axial piston machine of said type.
DE 41 30 225 C1 furthermore describes a hydraulic axial piston machine for installation into a gearing casing, which axial piston machine has a machine case which is open on one side and which has a connection block which closes off said machine case. The connection block has a pressure duct and a suction duct for the pressure fluid. A drive shaft of the axial piston machine projects out of the case and the connection block into the gearing casing and is mounted in the machine case and in the connection block. Said document makes no mention of measures for removing leakage liquid or for supplying lubricant to the axial piston machine or to the gearing. Further hydromechanical drives which have an axial piston machine and a gearing integrated therein are described for example in DE 10 2011 014 589 A1 and DE 42 35 697 A1.
The invention is based on the object of specifying a hydraulic axial piston machine of dry case type of construction for installation into a case, for example into a gearing casing, with which a reliable supply of lubricant to the axial piston machine and to the gearing for connection thereto is ensured in a simple and inexpensive manner. It is a further object to provide a hydraulic drive which comprises an axial piston machine of said type and a gearing.